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ASReml-S reference manual - VSN International

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8.6 Spatial analysis of a field experiment 98The iterative sequence has converged to column and row correlation parameters of0.68378 and 0.45851, respectively. The plot size and orientation is not known and soit is not possible to ascertain whether these values are spatially sensible. It is generallyfound that the closer the plot centroids, the higher the spatial correlation. This is notalways the case and if the highest between plot correlation relates to the larger spatialdistance then this may suggest the presence of extraneous variation [Gilmour et al., 1997,for example]. The plot of the sample variogram of the residuals is not trimmed and, ignoringthe unreliable contribution from extreme lags, appears in reasonable agreementwith the model.An extension to this model includes a measurement error or nugget effect term:> barley2.asr summary(barley2.asr)$loglik[1] -696.8227> summary(barley2.asr)$varcompgamma component std.error z.ratio constraintunits 0.1061724 4.859930e+03 1.787849e+03 2.718311 PositiveR!variance 1.0000000 4.577396e+04 1.667323e+04 2.745357 PositiveR!Row.ar1 0.6826403 6.826403e-01 1.022940e-01 6.673317 UnconstrainedR!Column.ar1 0.8437888 8.437888e-01 6.848144e-02 12.321425 Unconstrained> wald(barley2.asr)Wald tests for fixed effectsResponse: yieldTerms added sequentially; adjusted for those aboveDf Sum of Sq Wald statistic Pr(Chisq)(Intercept) 1 11918530 260 < 2.2e-16 ***Variety 24 11237959 246 < 2.2e-16 ***residual (MS) 45774The lattice analysis (with recovery of inter-block information) is:> barley3.asr summary(barley3.asr)$$loglik[1] -707.7857> summary(barley3.asr)$$varcompgamma component std.error z.ratio constraintRep 0.5287136 4262.361 6886.823 0.6189155 PositiveRowBlk 1.9344361 15594.957 5090.787 3.0633685 PositiveColBlk 1.8372487 14811.456 4865.667 3.0440754 PositiveR!variance 1.0000000 8061.759 1340.449 6.0142228 Positive

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